Speaking of imagined walls, here’s one from 1916, courtesy of the Library of Congress, http://www.loc.gov/pictures/item/2006681433/.
Female employees of the German munitions factory WASAG in their work clothes, 1916. The one on the right seems to have been “conscripted” (zwangsverpflichtet), though it is unclear on what basis. She was also apparently highly skilled insofar as she was a production manager (Produktionsleiterin) of some kind. Source: Haus der Geschichte Wittenberg, “Arbeiterinnen der WASAG Reinsdorf,” https://st.museum-digital.de/index.php?t=objekt&oges=69193